1. Field of the Invention
This invention relates to an automatic optometer which presents a plurality of visual targets to a subject while changing over the visual targets and measures the subject's visual acuity from the correction of the subject's response input.
2. Description of the Prior Art
In an automatic optometer of this type, a system has heretofore been adopted whereby when a subject's response input is not entered within a predetermined time, a visual target is advanced to the next step to shorten the examination time and to give the examination more continuity. However, this has been inconvenient because it is difficult for the subject to determine that a predetermined time has elapsed.
Further, even there is an inadvertent or erroneous operation in the subject's response input, it is judged as "wrong" in the apparatus because there is no correcting means, and re-examination is effected with the visual acuity value being reduced by one stage. This this has led to a disadvantage in that a correspondingly longer measuring time is required.